1. Field of the Invention
This invention relates to label applying devices for applying adhesive labels to articles and is particularly, although not exclusively applicable to label applying devices for labeling apparatus of weigh/price labeling machines in which articles (usually food items) are delivered by a conveyor to a weigh station where they are weighed and then to a labeling station where a label printed with the weight and price computed from the measured weight and other information such as date dates, goods description and appropriate bar codes is applied to the article.
2. Background Prior Art
U.S. Pat. No. 3,616,094 discloses such a label applying device in which a pickup assembly removes labels from a label-printing machine and affixes the labels on a prewrapped package as a different angular relation to the package than when picked up from the label-printing machine. The assembly includes a vacuum pickup tube rotatable through 180.degree. to pick up a label from the printing machine and move the label to a transfer position. A vacuum nozzle is rotatably supported on the pickup tube and has a cam follower positioned to engage a downwardly inclined cam on the downward motion of the pickup to the transfer position to rotate the labels through a predetermined angle and a label pickup pad to remove the label from the vacuum nozzle at the transfer position and affix the label to the prewrapped package. Thus the label is received from the printing machine by the pickup assembly at a first position, moved to a second position and, in so doing, is rotated through an angle of 180.degree. and, at the second position, is transferred to a pick pad which then moves the label to a further position at which it is applied to the package.
U.S. Pat. No. 4,124,436 discloses a label applying apparatus in which a label is rotated through a desired number of degrees of rotation before its application to an article in order that the label may be applied in a preferred orientation. A label dispenser delivers the label to a first vacuum foot which holds the label substantially parallel to the surface of the article upon which the label is to be placed. The label is then transferred to a second, reciprocating vacuum foot which rotates while it moves into contact with the article. Again the first transfer of the label is to an intermediate holding device from which the label is transferred to a second device which rotates the label and applies it to the package.
UK patent specification No. 814311 discloses a labeling machine having a carrier in the form of a narrow drum with space sets of suction ports around the drum for holding labels thereto. One port in each set is rotatable through a mechanical cam operated mechanism whilst the other ports are rendered inoperative to rotate the label with respect to the drum during the movement of the label from a gummer applying position to a position in which the label is applied to an article.
U.S. Pat. No. 4,425,181 discloses an apparatus for simultaneously applying individual "outserts" to multiple containers of pharmaceuticals. The containers are advanced along a conveyor and are stopped in groups by a gate assembly opposite to a transfer assembly including a rotatable pickup arm mounted for reciprocation between a retractor position adjacent a magazine containing the outserts and an extended position adjacent to container input path. Vacuum cups are provided from the pickup arm for engaging the outserts and pin and drive pin arrangement is utilised to control rotation of the pickup arm to reorientate the outserts only during an intermediate portion of travel between linear motion at the extended and retractable positions.
It is an object of this invention to provide a label applying device in which labels are transferred from a label supplied to an article to which the label is to be applied by single label holding means and to reorientate the label in the transfer operation utilising a mechanism which is both simple but precise to ensure both reliable and accurate positioning of the label.